This is a 54-week, open-label, randomized, parallel-group study of Atorvastatin compared to Simvastatin in mixed dyslipidemic patients with and without Type II diabetes mellitus. Patients with or without documented coronary heart disease (CHD) and/or peripheral vascular disease will be eligible. Following dietary therapy, all patients will be randomly assigned to begin dosing at the starting dose of randomly assigned atorvastatin or simvastatin and titrate to NCEP LDL-C goal or to maximum approved doses. In addition, the study will assess the mean percent change from baseline in lipid fractions and apolipoprotein B and the proportion of patients who achieve NCEP LDL-C goals at the end of 54 weeks of treatment. Safety parameters assessed will be the percent of patients with persistent transaminase elevations, and the percent of patients developing myopathy, in addition to routine safety monitoring.